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From:   Kees Cook <keescook@chromium.org>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Kees Cook <keescook@chromium.org>,
        Guillaume Tucker <guillaume.tucker@collabora.com>,
        David Laight <David.Laight@ACULAB.COM>,
        Arnd Bergmann <arnd@arndb.de>, linux-kernel@vger.kernel.org,
        kernelci@groups.io, linux-kselftest@vger.kernel.org,
        linux-hardening@vger.kernel.org
Subject: [PATCH 9/9] lkdtm/heap: Add init_on_alloc tests
Date:   Wed, 23 Jun 2021 13:39:36 -0700
Message-Id: <20210623203936.3151093-10-keescook@chromium.org>
In-Reply-To: <20210623203936.3151093-1-keescook@chromium.org>
References: <20210623203936.3151093-1-keescook@chromium.org>
MIME-Version: 1.0
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Add SLAB and page allocator tests for init_on_alloc. Testing for
init_on_free was already happening via the poisoning tests.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/misc/lkdtm/core.c               |  2 +
 drivers/misc/lkdtm/heap.c               | 65 +++++++++++++++++++++++++
 drivers/misc/lkdtm/lkdtm.h              |  2 +
 tools/testing/selftests/lkdtm/config    |  1 +
 tools/testing/selftests/lkdtm/tests.txt |  2 +
 5 files changed, 72 insertions(+)

diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index c185ae4719c3..9dda87c6b54a 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -127,6 +127,8 @@ static const struct crashtype crashtypes[] = {
 	CRASHTYPE(READ_AFTER_FREE),
 	CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
 	CRASHTYPE(READ_BUDDY_AFTER_FREE),
+	CRASHTYPE(SLAB_INIT_ON_ALLOC),
+	CRASHTYPE(BUDDY_INIT_ON_ALLOC),
 	CRASHTYPE(SLAB_FREE_DOUBLE),
 	CRASHTYPE(SLAB_FREE_CROSS),
 	CRASHTYPE(SLAB_FREE_PAGE),
diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c
index a3bb0577ed8b..3d9aae5821a0 100644
--- a/drivers/misc/lkdtm/heap.c
+++ b/drivers/misc/lkdtm/heap.c
@@ -174,6 +174,71 @@ void lkdtm_READ_BUDDY_AFTER_FREE(void)
 	kfree(val);
 }
 
+void lkdtm_SLAB_INIT_ON_ALLOC(void)
+{
+	u8 *first;
+	u8 *val;
+
+	first = kmalloc(512, GFP_KERNEL);
+	if (!first) {
+		pr_info("Unable to allocate 512 bytes the first time.\n");
+		return;
+	}
+
+	memset(first, 0xAB, 512);
+	kfree(first);
+
+	val = kmalloc(512, GFP_KERNEL);
+	if (!val) {
+		pr_info("Unable to allocate 512 bytes the second time.\n");
+		return;
+	}
+	if (val != first) {
+		pr_warn("Reallocation missed clobbered memory.\n");
+	}
+
+	if (memchr(val, 0xAB, 512) == NULL) {
+		pr_info("Memory appears initialized (%x, no earlier values)\n", *val);
+	} else {
+		pr_err("FAIL: Slab was not initialized\n");
+		pr_expected_config_param(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, "init_on_alloc");
+	}
+	kfree(val);
+}
+
+void lkdtm_BUDDY_INIT_ON_ALLOC(void)
+{
+	u8 *first;
+	u8 *val;
+
+	first = (u8 *)__get_free_page(GFP_KERNEL);
+	if (!first) {
+		pr_info("Unable to allocate first free page\n");
+		return;
+	}
+
+	memset(first, 0xAB, PAGE_SIZE);
+	free_page((unsigned long)first);
+
+	val = (u8 *)__get_free_page(GFP_KERNEL);
+	if (!val) {
+		pr_info("Unable to allocate second free page\n");
+		return;
+	}
+
+	if (val != first) {
+		pr_warn("Reallocation missed clobbered memory.\n");
+	}
+
+	if (memchr(val, 0xAB, PAGE_SIZE) == NULL) {
+		pr_info("Memory appears initialized (%x, no earlier values)\n", *val);
+	} else {
+		pr_err("FAIL: Slab was not initialized\n");
+		pr_expected_config_param(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, "init_on_alloc");
+	}
+	free_page((unsigned long)val);
+}
+
 void lkdtm_SLAB_FREE_DOUBLE(void)
 {
 	int *val;
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index e491bc571808..6a30b60519f3 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -86,6 +86,8 @@ void lkdtm_WRITE_AFTER_FREE(void);
 void lkdtm_READ_AFTER_FREE(void);
 void lkdtm_WRITE_BUDDY_AFTER_FREE(void);
 void lkdtm_READ_BUDDY_AFTER_FREE(void);
+void lkdtm_SLAB_INIT_ON_ALLOC(void);
+void lkdtm_BUDDY_INIT_ON_ALLOC(void);
 void lkdtm_SLAB_FREE_DOUBLE(void);
 void lkdtm_SLAB_FREE_CROSS(void);
 void lkdtm_SLAB_FREE_PAGE(void);
diff --git a/tools/testing/selftests/lkdtm/config b/tools/testing/selftests/lkdtm/config
index 849799bcfa95..013446e87f1f 100644
--- a/tools/testing/selftests/lkdtm/config
+++ b/tools/testing/selftests/lkdtm/config
@@ -5,3 +5,4 @@ CONFIG_FORTIFY_SOURCE=y
 CONFIG_HARDENED_USERCOPY=y
 # CONFIG_HARDENED_USERCOPY_FALLBACK is not set
 CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y
+CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt
index 30080cc15623..846cfd508d3c 100644
--- a/tools/testing/selftests/lkdtm/tests.txt
+++ b/tools/testing/selftests/lkdtm/tests.txt
@@ -21,6 +21,8 @@ VMALLOC_LINEAR_OVERFLOW
 READ_AFTER_FREE call trace:|Memory correctly poisoned
 #WRITE_BUDDY_AFTER_FREE Corrupts memory on failure
 READ_BUDDY_AFTER_FREE call trace:|Memory correctly poisoned
+SLAB_INIT_ON_ALLOC Memory appears initialized
+BUDDY_INIT_ON_ALLOC Memory appears initialized
 SLAB_FREE_DOUBLE
 SLAB_FREE_CROSS
 SLAB_FREE_PAGE
-- 
2.30.2